Bow trolley for electric vehicles



BOW TROLLEY FOR ELEGTHIIG VEHECLIES Film NWN "A, `1925? lfntented @et Htl KRAMER, l? BERLN, GERMANY, ASSIGNOR TOl HRTSTUFF-MIETALL AKTIEN- GrlESlEll'aLSClHEAlET (HAMETAG), OF BERlLlN-COFENIGM, GERMANY. n

130W TROLLEY MOR JELEG'IRC VEHICLES.

1 Application ledltfovemher 7, 1925, Serial No. what, and in Germany November l1, limit.

lilly invention relates to sliding contacts adapted'to slide along a donductor, such as an overhead wire, for the purpose of taking electric current therefrom, and conveying it to an electric car. or the like. 'lhe invention relates and is more particularly applicable. to bow collectors whichare resiliently held in sliding lcontact with the trolley wire..

'lhe objects of the present invention are to improve the electrical contact between such sliding collectors and the trolley wire, to reduce the wear on the bow and the wire and the formation of electric sparks, and to lessen the mechanical stresseson the overhead wire and the bow collector. l

These objects l attain by reducing the weifrht of the sliding art of the bow collector to the greatest possiblle extent, which lessons the oscillations of the collector and' its inertia. and thus enables it to more readily adapt itself to the irregularities of the trolley wire. Any unavoidable shocks that may be produced by vibratiehs of the ear or overhead `wire,,orloy defects in the latter, are thus reiideredfless serious, and they mechanical accordingly.. f

llt is important to make the sliding member bear continuall against the trolley wire also because it has been found that the sparking caused by this member when separating` from said wire gives rise to considerable disturb* ances in radio broadcasting receiving sets, particularly when the spark current is small.`

By the present invention the sliding action .between the sliding member and the trolley wire is improved, for in the sliding member the lubricant required for lubricating the contact surfaces is uniformly distributed in the body of the metal vso that no lubricant grooves liable to become inoperative are re i quired, and no lubricant, need be applied to the overhead wire. rlhe lubricant that is mired with the metal of the sliding member' preferably consistssof graphite, soot or the like, ln this way smooth Contact surfaces are A obtained,` their wear andl tear is reduced, and

' they therefore require lless attention.

,lill

Another feature ofthe invention relates to' the mechanical structurel of the sliding me'mber and its mounting upon the bow collector. llhe sliding member that contacts with, and

` takes the current from, the trolley wire is stress on the bow and trolley wire are reduced Amadefrom fine metal powder well mixed above a sliding member of low specific weight is obtained, which is lighter than that of the unmixcd metal, and which, nevertheless, is

far superior to the unmiXed metal in respectof its slippingand current taking effect. As

the sliding member is arranged at the en treme end of the bow collector, it is particularly important to have it as light as possible, because at this part of the collector it affects the inertia of the latter very considerably.

Because of the goed metallic Contact obtained with thenovel sliding member, the contacting surface of the same can be made smaller than in the'knownkinds of sliding members, so that it is capable of most accurately adapting itself to the. unavoidablenin regularities ofthe trolle wire and thus reducing sparking from w iiehthe above inentioned evils arise.v ing surface has the additional ed'ect of reduc ing the weight of the entire sliding member. v

The metals whose powders are most suit- "lll Sinallness of the contactable for producing the sliding. member are l those bearing a high degree of conductivity,y

such as copper, Copper alloys, aluminum etc. and mixtures of these metals. Aluminum is the most suitable for very light sliding members. lBy the use of aluminum powder mixed with graphite a porous body is obtained whose specific weight can be reduced to 30% below that lof rolled aluminum.

Any known method of making such bodies of pressed metal and carbonaeeous powders, with or without an admixture of binding agent, may be employed. A

A- manner of carrying out the invention is shown in the drawing in which lFig. l is a front view, partly in section,.of a bow col lector, llig. 2 a sectional view of a corner of ico ma l

the bow collectorv and-h`ig. 3 a seetiomtaken.

at right angles to that of Fig. 2, of the sliding member bearing against a trolley wire.

To facilitate manufacture, the sliding member 1 is made of several parts or blocks. For street cars or trams, Where the bow collector 2 assumes an inclined position, the sliding blocks are made of the cross section shown in Fig. 3. The contacting sides 3 and 4 form an obtuse angle and are arranged so that the one side or the other bears aloiitgr the whole of its length against .the overhead wire 5 as shown according as the car travels in the one or the other direction. The two I halves of the block at the two sides of the plane, indicated by the line A B and extending vertically to the surface of the drawing, are symmetrical audits external surfaces 6, 7

run parallel to the plane through A, B. The

bottom surface 8 of the block may be made fiat or curved. In'the drawing it is shown flat and extends at right angles to the plane through A, B. In this bottom side 8 a groove with converging sides is made into which is fitted a rolled iron bar 9 of dove-tail section. The individual blocks l are connected iii this way by the rod 9. The ends l0 ofthe rod 9 are threaded as indicated in Fig. 2 and the blocks l are forced together laterally by screw nuts 11. The individual blocks 1 are thus forced into intimate contact and form a rigid unit with the rod 9. Projecting from the threaded sections 10 are pins 12 that fit into the ends of the bow 2 and are fixed in the same. When the rod 9 is taken out of the bow 9.-, the blocks 1 can be removed and replaced.

By shaping the cross section of the blocks as shown in Fig. 3, so that the sides 6 and 7 run parallel to 'each other, the amount of contacting surface bearing against the trolley wire is always maintained the same as the block wears down. The block may be worn down almost as far as the rod so that. its material is utilized to the greatest possible extent. This feature is aifected favorably by the angle at which the surfaces 3 and 4 are placed to each other, as this requires the smallest possi-ble qiiantit of block material for the arranveinent of the rod 9, this quantity being indicated in Fig. 3 by the crosshatched surfaces 13 and 14.

The sliding blocks may, of course, be fixed on the rod 9 in some other manner if desired. For example, a round rod may be used that is threaded through boreholes in the blocks l. An advantage of the illustrated construction, however, is that the blocks 1 are secured against rotation without the use of any special means therefor.

I claim:

1. In combination with a bow-collector for street cars and the like, a sliding contact consisting of a porous body formed of powdered. metal or metals of relatively light Weight and graphite intimately and uniformly mixed therewith and compressed to the desired shape. Y

l 2. In combination with a bow-eollector for street cars and the like, a sliding Contact consisting of a porous body formed of powdered aluminum and graphite intimately and uniformly mixed therewith and compressed to the desired shape.

3. In combination with a bow-collector for street cars and the' like, a sliding contact consisting. of a porous body formed of light weight powdered metal, and graphite intimately and uniformly mixed therewith in amounts of 10 to 25% and compressed to the desired shape.

-4. In combination with a bow-collector for street cars and the like, a sliding Contact consisting of a porous body formed of relatively light weight powdered metal, and graphite intimately and uniformly mixed therewith and compressed to the desired shape, and a stiffening member for said contact.

In testimony whereof I atlix my signature.

1 ERVIN KRAMER. 

